This invention relates in general to magnetic tape recording/reproducing apparatus and, more particularly, this invention relates to an assembly for latching a magnetic tape reel to a hub so that the reel is accurately located on the hub and slippage between the reel and hub is prevented during rotation of the reel.
Magnetic tape recording/reproducing apparatus are widely used to record analog or digital information on tracks on magnetic tape. Generally, the magnetic tape is transported from one reel, past a magnetic head assembly, and onto another reel. Typically, the magnetic head assembly includes either stationary magnetic heads (which record and reproduce information on tracks which extend longitudinally of magnetic tape) or rotary magnetic heads (which record and reproduce information on slant tracks on magnetic tape). The reels between which the magnetic tape is transported are typically mounted either in a coplanar or coaxial relationship. In any case, it is desirable that a magnetic tape reel be accurately located on a hub and that slippage between the reel and hub be prevented during rotation of the reel. If a reel is not located accurately on the hub, then transport of tape onto and off of the reel may produce uneven tape packs and potential damage to the tape. Such damage results in degraded information being recorded on and reproduced from the tape. Moreover, if the reel slips relative to the hub during rotation of the reel with varying tape tension, resulting in recorded and reproduced information degradation.
Known arrangements for latching a reel to a hub have not been entirely successful. Thus, U.S. Pat. No. 2,833,488, issued May 6, 1958, Inventor Kerber, discloses an expansible core adaptor for mounting a core of web material upon a rotatable shaft. The core adaptor includes a cylindrical shaped body having a circumferential annular groove. A resilient, rubber O-ring is disposed in the groove and backs up a closely coiled garter spring which extends above the groove to radially engage the core. Because the inner surface of the core is smooth, this arrangement is disadvantageous because of the likelihood of axial slip between the core and the core adaptor. U.S. Pat. No. 4,109,878, issued Aug. 29, 1978, Inventor Osawa, discloses a cassette tape winding apparatus including a V-shaped groove formed on the inner circular surface of a reel. A hub (upon which the reel is mounted) has an annular circular groove. The groove contains a donut-shaped rubber tube and a circular spiral spring which extends into the V-shaped groove of the reel. The rubber tube is subject to degradation over the life of the apparatus, thus requiring time consuming and expensive replacement. U.S. Pat. No. 3,817,469, issued June 18, 1974, Inventors Moscitti et al, discloses a self-positioning reel-latching hub including a helical coil spring captured in a groove of the hub. The spring engages an inner edge of a tape reel to axially locate the reel relative to the hub. The engagement force is insufficient to prevent slippage of the reel relative to the hub when they are rotated. Instead, a complex latching arrangement is described to prevent slippage. None of the arrangements disclosed in these patents provide a simple, reliable and effective solution to the problem of latching a reel to a hub.